package org.tigris.scarab.util;

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 * any, must include the following acknowlegement: "This product includes
 * software developed by Collab.Net <http://www.Collab.Net/>."
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import org.apache.oro.text.regex.MalformedPatternException;
import org.apache.oro.text.regex.Pattern;
import org.apache.oro.text.regex.PatternCompiler;
import org.apache.oro.text.regex.Perl5Compiler;
import org.apache.oro.text.regex.Perl5Matcher;
import org.apache.oro.text.regex.Perl5Substitution;
import org.apache.oro.text.regex.Substitution;
import org.apache.oro.text.regex.Util;
import org.apache.oro.util.Cache;
import org.apache.oro.util.CacheLRU;

/**
 * This is a utility class for processing regular expressions
 * based on oro.
 *
 * @author <a href="mailto:dabboussaxess.com">Hussayn Dabbous</a>
 * @version $Id: ReferenceInsertionFilter.java 7365 2003-03-15 21:56:59Z jon $
 */
public class RegexProcessor extends Object
{

    protected static Cache patterns      = new CacheLRU();
    protected static Cache substitutions = new CacheLRU();

    private PatternCompiler compiler;

    public RegexProcessor()
    {
        compiler = new Perl5Compiler();
    }

    public String process(String input, String regex, String substitution) throws MalformedPatternException
    {
        String result = input;
        Pattern pattern = (Pattern) patterns.getElement(regex);
        if (pattern == null)
        {
            pattern = compiler.compile(regex);
            patterns.addElement(regex, pattern);
        }

        Substitution subst = (Substitution) substitutions.getElement(substitution);
        if (subst == null)
        {
            subst = new Perl5Substitution(substitution);
            substitutions.addElement(substitution, subst);
        }

        Perl5Matcher matcher = new Perl5Matcher();

        result = Util.substitute(matcher, pattern, subst, input, Util.SUBSTITUTE_ALL);

        return result;
    }

}
